Aspirin is a drug that has been around for 100 years. Nevertheless, The National Institute of Health is currently sponsoring at least 35 studies designed to probe aspirin's therapeutic role in conditions as diverse as hearing loss and allergies. It is touted as an anti-heart attack and anti-stroke medicine and is considered the number one medication for every type of arthritis.
The "humble" aspirin still remains the gold standard for pain relievers as well as the cheapest. For example, you can pay more than 20 times the cost of aspirin for an anti-inflammatory agent, which requires a prescription, and still not experience better pain relief. No drug in the world outsells aspirin and yet all the drug companies are still searching for a "better" aspirin.
In many cases, aspirin is the drug of choice and the mainstay of arthritis therapy. The common dosages of aspirin (325 mg or 500 mg), however, only provide relief of the symptom of arthritis (pain). In order to achieve effective control of inflammation, the cause of arthritis, daily dosages of greater than 5,000 mg are needed. At these higher dose levels the rate of success is over 70%. However, the success rate falls off dramatically and with 2500 mg. for example, it is less than 10%. Thus, the cause of failure or the lack of success with aspirin therapy is the use of inadequate dosages.
At the present time there is no satisfactory aspirin product available that may be used in the relatively large dosages that are required for anti-inflammatory activity. In addition, in many cases, pain and inflammation may not be relieved immediately, and treatment is a cumulative effect to obtain a "therapeutic level".
Unfortunately, aspirin exhibits a number of undesirable side effects. The most commonly experienced side effects are nausea, gastric upset (heartburn) and pain. At low analgesic dose levels these side effects will generally occur in about 2-10% of adult users of aspirin. With higher anti-inflammatory dosages the incidence of these undesirable side effects generally rises to about 25%.
The side effects are topical, as aspirin is an insoluble drug and it's undissolved particles tend to adhere to the stomach mucosa, causing irritation, inflammation and injury. The topical nature of these detrimental side effects has been established by gastroscopy and autopsies. Erosion, for example, around undissolved particles of aspirin in the stomach have been photographed. Because aspirin is a direct irritant to the gastrointestinal mucosa it's effects are both cumulative and persistent.
Topical side effects do not occur, however, when aspirin is administered in solution form. While all users of aspirin could benefit greatly from the advantages of it's soluble form, older patients are in particular need of such a soluble aspirin product because arthritis is a dreaded disease of old age. The elderly, as a group, are the largest users of aspirin and, at the same time, the most vulnerable to it's acute side effects. The incidence of these detrimental side effects is about 25% among geriatric patients.
Owing to reduced stomach motility and increased emptying time which occur with aging, insoluble aspirin particles remain in contact with the stomach mucosa much longer in the elderly, thereby intensifying the undesirable side effects. In addition, there are approximately 15 million people, in the U.S., who experience some degree of difficulty in swallowing tablets and other solid medications. Older people, once again, are effected as esophagus muscles weaken with age and make swallowing much more difficult.
As is generally well known, there are some soluble aspirin products that are available commercially in the U.S., and Europe. Unfortunately, they all suffer from one or more shortcomings which have prevented their universal acceptance, especially in the United States. For example, the only soluble product which is commercially available in the United States, "Alka Seltzer", contains 567 mg of sodium per 325 mg of aspirin (1,750 mg per 1,000 mg of aspirin).
In order to provide anti-inflammatory activity with Alka Seltzer it would require daily ingestion of more than 8,000 mg of sodium. This amount of sodium makes it totally unacceptable for regular aspirin therapy. Not only is this sodium level extremely high, for the population in general, but it can not be tolerated by many of the elderly arthritic who are also on a restricted sodium diet.
Other products available in Europe either also contain sodium, dissolve incompletely or could not win FDA approval in the U.S. for some reason. Despite their shortcomings, however, these products still capture a large share of the market for aspirin products from Europe to Mexico.
Numerous attempts to produce a soluble aspirin product, in the past, have included salts of lithium, sodium, calcium and magnesium. None of these soluble aspirin salt products were proven to be totally satisfactory. It is generally well recognized in the art that these particular salts are not only unstable, but also produce a number of undesirable side effects.
Even though potassium possesses many properties that would make it an ideal compound for this purpose, potassium aspirin has never been developed as a satisfactory commercial product. The primary reason is that the salts formed with potassium form bitter, unpalatable solutions. Thus, potassium acetylsalicylate (potassium aspirin) would be an ideal aspirin replacement if it could be made palatable.